ATP TURNOVER IN ISCHEMIC AVIAN PECTORAL MUSCLE

ATP turnover in Pekin duck pectoral muscle was estimated using phospho rus magnetic resonance spectroscopy during complete ischaemia induced by cardiac arrest. ATP turnover remained at or above estimated resting perfused values for at least 55 min following the onset of cardiac ar rest. PCr was undetectable at 77.5 min of ischaemia, at which time ATP content had decreased by 47% (not statistically significant) from res ting perfused levels (9.13 +/- 0.27 mu mol.g(-1)). Average rate of PCr hydrolysis decreased progressively during ischaemia from 0.88 +/- 0.2 8 mu mol.min(-1).g(-1) during the initial 7.5 min to 0.11 +/- 0.04 mu mol.min(-1).g(-1) over the interval 47.5 to 62.5 min following cardiac arrest. Lactic acid was calculated to accumulate at a sustained rate of approximately 1 mu mol.min(-1).g(-1) during 62.5 min of ischaemia. Progressive accumulation of tissue lactate was confirmed in one animal using H-1 NMR. These data do not support the hypothesis that complete ischaemia will provoke a rapid metabolic depression in duck skeletal muscle.